Robust Control of Once-Through Canadian Supercritical Water-Cooled Reactors

The Canadian SuperCritical Water-cooled Reactor (SCWR) is a once-through pressure tube–type SCWR under development in Canada. It is a multivariable system with strong cross coupling and a high degree of nonlinearity. The outputs are sensitive to disturbances, and the variations in the thermal parameters should be limited to avoid thermal stress to its components. Therefore, designing an adequate control system is challenging. In this paper, robust multivariable feedback control and feedforward control are proposed to design the control system of the Canadian SCWR. Three uncertainty sources are considered: unmodeled uncertainty, linearization uncertainty, and model reduction uncertainty. These uncertainties are evaluated taking into account all aspects affecting the linear dynamic model used in the robust controller synthesis, and the uncertainty bounds are determined to cover the uncertainties. The robust feedback controller is synthesized using the μ-synthesis approach. The feedforward control is added to the robust feedback control to further improve the control performance. It is obtained through disturbance compensation features for a feedforward controller. The control performance of the hybrid control system is evaluated based on the nonlinear simulation by introducing different setpoint changes. The designed control system can stabilize the Canadian SCWR, and the control performance is satisfactory.